1. Field of the Invention
The invention relates to an earphone comprising a speaker unit and an earpiece for being worn in a user's ear canal and/or concha; the invention also relates to the use of such an earphone.
2. Description of Related Art
In general, the earpiece of an intra-auricular earphone may be of the “one-size-fits-all” or generic type, wherein the earpiece comprises a shell made of a soft, flexible material and having an outer surface of standard shape, with the soft earpiece, typically delivered in a number of sizes (typically 3 or 4), adapting to the individual shape of the user's concha and ear canal due to its flexibility.
Alternatively, the earpiece may comprise a shell made of a relatively hard material and having an outer surface individually shaped according to the measured inner shape of the user's ear canal and outer ear. The measurement usually is done by taking an impression of the user's ear and subsequent laser scanning of the impression or by direct laser scanning of the user's ear. Such earpieces are known as customized earpieces. Earphones comprising a customized shell described, for example, in US 2004/0201139 A1, DE 101 11 636 B4, DE 10 2006 007 032 A1, EP 1 629 808 A1, EP 1 595 515 A1, GB 2,355,129 A, U.S. Pat. No. 7,139,404 B2 and U.S. Pat. No. 7,016,512.
U.S. Pat. No. 7,139,404 B2 and U.S. Pat. No. 7,016,512 relate to modular systems including a CIC (Completely-In-the-Canal) earphone comprising an earpiece, which may be either generic or customized and into which a speaker unit is inserted in a detachable manner, with the speaker unit being connected by wires to a BTE (Behind-The-Ear) component. The system may be used as an earphone for music from an external device or as a stage monitor for musicians. Also US 2007/0036385 A1 and US 2007/0053540 A1 relate to modular earphones comprising a speaker unit, which is inserted into an earpiece, wherein the earpiece could be either a generic earpiece or a customized earpiece and wherein the earpiece may be replaced, if the earpiece deteriorates during use; the speaker unit may comprise a two-way speaker.
US 2006/0285715 A1, U.S. Pat. No. 5,878,070 and the Knowles Application Note concerning TI-29, Report 10559-2 by M. T. Killion, relate to high end earphones comprising an acoustic damper and a resonator portion for optimizing the frequency response of the earphone, wherein the damper and the resonator portion are part of the speaker unit which is connected to an earpiece. The damper is provided within the resonator which may be a quarter-wave resonator, and is replaceable by a damper of the same kind if the damper becomes deteriorated during use of the earphone.
When an intra-auricular earphone, which closes the ear canal, is worn, the transfer function of the ear is changed in that the quarter-wave resonance of the ear canal and the amplification of the pavilion disappears, which effects cause an uncomfortable sensation to the user. Hence, it is desirable to provide the earphone with a frequency response suitable for restoring the natural open ear gain, in particular, the quarter wave resonance of the ear canal, as far as possible in order to provide for a natural hearing impression to the user when wearing the earphone.
It is an object of the invention to provide for an intra-auricular earphone which allows for an optimization of the frequency response, and, in particular, for an individual adjustment of the frequency response of the earphone to the specific user in a particularly simple manner.